Method and apparatus for compression molding of a graphite plate

Abstract

A moveable table has a target area defined thereon. A hopper filled with an accurate amount of the moldable graphite mixture sifts and meters this mixture through screens onto the target area. The moveable table then shifts to place the target area over the mold cavity, whereupon a door is opened to allow the graphite material to drop evenly into the mold cavity. The compression mold includes a moveable ring surrounding the mold cavity which defines a well for receipt of the graphite material. After compression molding, the mold is opened and the ring is lowered to expose the finished part for removal.

1 . An apparatus for loading a mold cavity with particulate moldable material comprising: 
 a moveable table member;    a target area defined on said table member, said target area comprising an opening in said table member;    material delivery means for delivering a measured quantity of the particulate moldable material onto said target area;    a door positioned under said target area;    means for moving said moveable table member between a first position where said target area is loaded and a second position where said target area is positioned over the mold cavity; and    means for selectively opening said door to release the particulate moldable material into the mold cavity.    
   
   
       2 . The apparatus of  claim 1  wherein said material delivery means comprises a hopper device driven in reciprocating fashion across said target area.  
   
   
       3 . The apparatus of  claim 2  wherein said hopper device comprises a tapering enclosure having an opening at the bottom thereof and defining an interior space, and further comprising a screen positioned in said interior space for sifting the particulate moldable material loaded therein.  
   
   
       4 . The apparatus of  claim 3  wherein said hopper device further comprises a rotating blade device positioned within said enclosure and further comprises a screen positioned above said rotating blade device and arranged such that it is vibrated by said rotating blade device.  
   
   
       5 . The apparatus of  claim 4  further comprising means for driving said rotating blade device in response to said reciprocating motion of said hopper device and means for maintaining the direction of rotation of said rotating blade device during reversal in the direction of travel of said hopper device.  
   
   
       6 . An apparatus for compression molding items from particulate moldable material comprising: 
 a compression mold having a mold core and a mold cavity, wherein said mold cavity has a selectively moveable ring positioned around the periphery thereof;    a moveable table member positioned proximate said compression mold;    a target area defined on said table member, said target area comprising an opening in said table member;    material delivery means for delivering a measured quantity of the particulate moldable material onto said target area;    a door positioned under said target area for selectively releasing the particulate moldable material into the mold cavity; and    means for moving said table member to place said target area over said mold cavity; and    means for selectively opening said door and thereby releasing said particulate moldable material into said mold cavity.    
   
   
       7 . The apparatus of  claim 6  wherein said material delivery means comprises a hopper device driven in reciprocating fashion across said target area.  
   
   
       8 . The apparatus of  claim 7  wherein said hopper device comprises a tapering enclosure having an opening at the bottom thereof and defining an interior space, and further comprising a screen positioned in said interior space for sifting the particulate moldable material loaded therein.  
   
   
       9 . The apparatus of  claim 8  wherein said hopper device further comprises a rotating blade device positioned within said enclosure and further comprises a screen positioned above said rotating blade device and arranged such that it is vibrated by said rotating blade device.  
   
   
       10 . The apparatus of  claim 9  further comprising means for driving said rotating blade device in response to said reciprocating motion of said hopper device and means for maintaining the direction of rotation of said rotating blade device during reversal in the direction of travel of said hopper device.  
   
   
       11 . A method of loading a mold cavity of a compression mold with particulate moldable material comprising: 
 positioning a moveable table member proximate the compression mold, 
 wherein said table member has defined thereon: 
 a target area comprising an opening in said table member;  
 material delivery means for delivering a measured quantity of the particulate moldable material as a layer onto said target area; and  
 a door positioned under said target area for selectively releasing the particulate moldable material into the mold cavity;  
 
   loading said target area from said material delivery means; selectively moving said table member to place said loaded target area over the mold cavity; and    opening said door to release said particulate moldable material into the mold cavity to create a layer of particulate moldable material therein.    
   
   
       12 . The method of  claim 11  wherein said material delivery means comprises a hopper device driven in reciprocating fashion across said target area.  
   
   
       13 . The method of  claim 12  wherein said hopper device comprises a tapering enclosure having an opening at the bottom thereof and defining an interior space, and further comprising a screen positioned in said interior space for sifting the particulate moldable material loaded therein.  
   
   
       14 . The method of  claim 13  wherein said hopper device further comprises a rotating blade device positioned within said enclosure and further comprises a screen positioned above said rotating blade device and arranged such that it is vibrated by said rotating blade device.  
   
   
       15 . The method of  claim 14  further comprising driving said rotating blade device in response to said reciprocating motion of said hopper device and maintaining the direction of rotation of said rotating blade device during reversal in the direction of travel of said hopper device.  
   
   
       16 . A method of compression molding a molded part with particulate moldable material comprising: 
 providing a mold cavity having a peripheral rim defined thereon, with a moveable ring member, wherein said ring member surrounds said rim of said mold cavity;    positioning a moveable table member proximate said mold cavity, wherein said table member has defined thereon: 
 a target area comprising an opening in said table member;  
 material delivery means for delivering a measured quantity of the particulate moldable material as a layer onto said target area; and  
 a door positioned under said target area for selectively releasing the particulate moldable material into said mold cavity;  
   layering the particulate moldable material onto said target area on said table member from said material delivery means;    selectively moving said table member to place said target area over said mold cavity;    opening said door to release the moldable material into said mold cavity to thereby create a layer of particulate moldable material therein;    forcing a mold core against said mold cavity and said moldable material placed therein, thereby compressing said moldable material, and heating said moldable material to form a molded part; and    moving said mold core and said ring member to expose the molded part.    
   
   
       17 . The method of  claim 16  wherein said material delivery means comprises a hopper device driven in reciprocating fashion across said target area.  
   
   
       18 . The method of  claim 17  wherein said hopper device comprises a tapering enclosure having an opening at the bottom thereof and defining an interior space, and further comprising a screen positioned in said interior space for sifting the particulate moldable material loaded therein.  
   
   
       19 . The method of  claim 18  wherein said hopper device further comprises a rotating blade device positioned within said enclosure and further comprises a screen positioned above said rotating blade device and arranged such that it is vibrated by said rotating blade device.  
   
   
       20 . The method of  claim 19  further comprising driving said rotating blade device in response to said reciprocating motion of said hopper device and maintaining the direction of rotation of said rotating blade device during reversal in the direction of travel of said hopper device.